Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
nang ma » tang ma, sang ma, nang cao
lang xa » lang ha, dang xay, lang van
hieu ve » hieu va, hieu van
hanh di » hanh de, hang di, danh di
cac loc » cac lop, cac toc, cac hoc
te sai » te tai, te bai, te lai
loc va » hoc va, luc va
sai ky » sac ky
ve cac » va cac, vien cac

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te sai ky ((nang ma) or (lang xa)) hoi. hieu ve cac loc va ((hanh di) OR (hanh vi)) cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sai ky ((nang ma) OR (lang xa)) hoi. hieu ve cac loc va ((hanh di) OR (hanh vi)) cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sai ky ((nang ma) or (lang xa)) hoi. hieu ve cac loc va ((hanh di) OR (hanh vi)) cua viet".
• Adding a wildcard symbol may retrieve word variants: te sai ky ((nang ma) or (lang xa)) hoi. hieu ve cac loc va ((hanh di) OR (hanh vi)) cua viet*.